Running static LAN ip address connecting to a router modem. When I plug in through a switch I can ping the gateway and connect to the internet at D/U 18.5Mbs / .24Mbs. When I plug the 30M cat 5e cable into my NIC directly with out the switch I can't even ping the gateway!?? Totally repeatable and consistent behaviour. Other machines can do it with out the switch and this one has connected ok in the past. The router (Draytek 2700) has the MAC address cached and is supposedly not blocking it.

Any ideas what on earth is going on here?